In the games

According to legend, long before the events of Pokémon Black and White, the Twin Heroes shared a powerful dragon. However, they could not decide whether to pursue truth or ideals, so the dragon split into Reshiram and Zekrom and each followed one of the brothers. Since they were both born from the same dragon, neither could defeat the other and the brothers declared that there was no right side. However, eventually their sons continued the fight and both the dragons started to battle again, destroying the Unova region with their fire and lightning powers before disappearing. Both dragons' bodies were destroyed, and they transformed into the Light Stone and Dark Stone, respectively.

Pokémon Black and White

The Dark StoneB/Light StoneW resides in Dragonspiral Tower, while the Light StoneB/Dark StoneW once resided in the Relic Castle (which was excavated and put on display in the Nacrene Museum prior to the events of Black and White). The Dark StoneB/Light StoneW is revived as ZekromB/ReshiramW and called upon by N to create a world where Pokémon and people are separate. Team Plasma also tracked down that the Light StoneB/Dark StoneW should have been located in the Relic Castle and searched it, only to find that it was gone. Professor Juniper and Lenora then realized that the "ordinary stone" displayed in the museum was actually the Light StoneB/Dark StoneW, and request that the player come to Nacrene City immediately via Xtransceiver. Lenora then gives the Light StoneB/Dark StoneW to the player, who must then revive the Legendary dragon within it and battle N. This revival and battle occur at N's Castle, a structure that emerged from the ground around the Pokémon League.

Once the player enters the Hall of Fame for the first time, N's Zoroark will stop blocking a cliffside path at Victory Road and will lead the player down to the ruins of N's Castle. Upon entering the castle, N requests that player head to the deepest chamber. In the throne room, N recalls the fateful battle two years ago and asks the player to battle him and his ZekromB2/ReshiramW2. After the player defeats him, N reverts his dragon into its primordial stone and hands it to the player, with instructions to bring it to Dragonspiral Tower in order to summon and capture ZekromB2/ReshiramW2.

Zekrom's body was destroyed and changed into this stone. It is said to be waiting for the emergence of a hero.

In the anime

Zekrom's Dark Stone

Reshiram's Light Stone

The Dark and Light Stones appeared in the movies Black—Victini and Reshiram and White—Victini and Zekrom. They were only referred to individually in the dub, only being collectively referred to as the Dragon Stones in the original version. As embodiments of the dragons, the stones can glow according to the inhabitants' power source, with the Light Stone glowing red from Reshiram's fire and the Dark Stone glowing blue from Zekrom's electricity. They first appeared under the ownership of the Heroes of Truth and Ideals, as the hibernating forms of the fatigued dragon Pokémon. The stones were hidden below the Sword of the Vale by the heroes. In Black—Victini and Reshiram, Ash awakens Reshiram while Damon awakens Zekrom; in White—Victini and Zekrom, it is the other way around. Once both dragons were awakened, neither stone is seen again, as the stones are the dragons.

An item called the "Golden Dark Stone" appeared in Explorers of the Hero's Ruin!, where it was hidden in the Hero's Ruin. It was sought by Cedric Juniper. Unlike the Dark Stone, this item was golden instead of black, and merely summons Zekrom instead of being its dormant form.

The Light Stone appeared in Ash and N: A Clash of Ideals!, where it was found in the White Ruins by Cedric Juniper. N soon snatched it away, claiming that he wanted to ask Reshiram why it had attacked Team Plasma's castle years before. Ash tried to chase after him, but got stuck in a sinkhole. N tried to help him, but ended up falling down the same hole with Ash. Using Pikachu, Pignite, Krookodile, and Charizard, Ash was able to dig them a way back to the surface, where Team Plasma had started an attack on the White Ruins, intending to get the Light Stone for themselves. When Colress used his Pokémon Control Device on Pikachu, forcing it attack Ash and his friends, N surrendered the Light Stone to Team Plasma in exchange for Ash's safety. Ghetsis then proceeded to conduct a ritual to awaken Reshiram, successfully restoring the Vast White Pokémon to its true form.

In the manga

In the Pokémon Adventures manga

The Dark Stone in Pokémon Adventures

The Light Stone in Pokémon Adventures

The Light Stone and Dark Stone resided at the Desert Resort, where they were found and excavated by Clay and his mining team. After investigating the stones, he felt worried and called Lenora to come and investigate them with her expertise on ancient artifacts. Lenora took both stones to her museum, but only made the Dark Stone discovery public so that the Light Stone could be kept a secret. Later, Lenora called Drayden to help her investigate the stones, which helped them realize that they were actually Zekrom and Reshiram.

The Dark Stone was sought out by Team Plasma, who managed to steal it after deceiving Black. The Dark Stone was taken to N, who awakened Zekrom at the Dragonspiral Tower and converted it to his side to become the Hero of Ideals. The Light Stone rolled towards Black and chose him to wield Reshiram as the Hero of Truth. Later, Reshiram was awakened at the Pokémon League, where Black used it to battle N's Zekrom and won. After the battle was over and Team Plasma had been defeated, Reshiram started reverting into its stone form once again. Ghetsis, wanting to get revenge on Black for foiling his plans, used Colress's Beheeyem to push Black closer to the forming stone, causing him to get sucked into it as well. The Light Stone then floated away, leaving Black's current whereabouts a mystery.